Boiler construction



June 25, 1929 J. A. FREIDAY 1,718,344

BOILER CONSTRUCTION Filed May 27, 1924 2 Sheets-Sheet 2 III iii VAfi/c/gu Patented June 1929 BOILER ooNsmBUcTIoN.

streams,

. Applicationjfiled May 27,1924. Serial met-16, 126."

My invention aims to provide certain improve'nn-nts in boilers andparticularly in boilers having water walls such as have. ben describedin certain recent applicationsot' Thomas E. Murray. of which No.(378,443 will serve as an example.

The accompanying drawings illustrate an embodiment of the invention. 1'

Fig 1 is a lm'ig-itudinal section more or less diagrammatic, of aboilerto which my i-niprovement is applied;

Fig. 2 is an elevation of an auxiliary "suQ perheater shown separatelyfrom theother partsof the boiler;

Fig.- 3 is a diagram, in ele.vation,'ot a t'ubuthe CH'Cllllll'lngconnections lar water walland thereof;

Fig. ,4 is a detail in cross-section.

' Referring to the embodiment of the inven-j tion illustrated, thefurnace is-provided with u radiant heat from the fire bed and therefore,

stoker grates l at opposite sides ofthc furnace chamber indicated as awhole at 2 m wlnchthe combustion of the gases takes place.

' The. main boiler tubes 3 extend between headers 4 and 5; Above theseare the supplementary boiler tubes 6 extending between headers pass outby the pipe 10 -to the stack.

One or more of the walls is provided with an inner water screen or wallmade up of tubes 11 with lateral flanges 12 as shown in crosssection in,Fig. 4. These tubes communicate at the upper end with a header 13 andat the low er end with a header 14. Above the drum 13 there is a muddrum 15 connected with the headers 4: by tubes 16 constituting acontinuation of the water wall. The tubes 11 of the water wall leadthrough headers 13 and pipes 13 to the drum 9, whence'pipes 14 returnwater to the header 14. A very high efficiency is obtained by-the use ofsuch a water wall. The pipes'thereof may be arranged in varipuslocations and groups according to the design of the furnace and boiler.

Ordinarily superheaters for water tube boilers of the class illustratedcomprise small tubes such, for example, as 17 extending across above thewater tubes. The steam from the main drum 9 passes by a pipe 18 tothetubes 17, whence it passes to an outlet pipe 19 and thence to thesteam engine.

, I propose, however, toprovide an auxiliary stiperheater which serves adouble-purpose, the efficient super-heating of the steam and protectionof the water wall headers or drums.

Such a superheater, for example, comprises a screen of vertical tubes 20located on the inner side of the drums'13 and 15. a Fig. 2 is a View ofthis auxiliary superheater frornthe'outer side, omittingflthe water wallof the boiler. The steam passes'by any suitable piping, indicateddiagrammatically by the dotted line121 to a header 22 on the cute sideofsthe boiler, thenceaby small tubes 23 passing through the spaces.between the'tubes 16 to thetubes'20 of-the auxiliary 'superheat-' er;thence by similar cross tubes 24 from the lower ends of the tubes 20through the spaces between the tubesl'l' to a header 25 and out by :1.pi 16-26 totlle'point of consumption.

' T 'e auxiliary superheater is exposed to the like the water wall, ismost highly efficient in transmitting heat to the steam within thetubes. Thus a .very small quantity of piping in the auxiliarysuperheater 'may be substituted for a consider able quantity of pipingtaken away from the usual or main superheate'r located above-the tubes 3and heated passed around the tubes 3. The auxiliary heater forms also ashield partycovering the drums 13 and 15....1t1nay in fact be arrangedto shield in' whole or ijt part any pipes which exposed to the air onthe outside so as to itself -be protected from overheating.

Though I have described with great par- .80 only by convection by thegases which have ticularity of detail a certain embodiment of myinvention, yet it is not to; be understood therefrom that theinventionis restricted to the particular embodiinentdisclosed. Va-

rious modifications maybe made by those skilled in the art withoutdeparture from the invention as defined in the following claims. -100water wall with a top header 13 and a shield on the inner side of said'mud drum and top I t heiider eoni-pi-ising tubes 20 extending over I-.;within" t;he"outer shell of the furnace, a shield of verticalflliid-carrying tubes over the inner side of said header, a headeroutside the fur-- nace and transverse tubes passing betweensaid watertubes and connecting the outside 1 header to the tubes of said shield.

In witness whereof,. I have hereunto JAY A. FREIDAY.

signed my name;

